The present invention relates to data processing systems, and more particularly, to automated apparatus for selectively loading magnetic tape cartridges from a library into a tape drive.
Tape drives are widely used as peripheral memory storage devices for computer systems. In the early days of computer processing, tape drives typically utilized open reels of one-half inch magnetic tape which were manually loaded onto so-called vacuum column tape drives. Tape cartridges have largely supplanted open reels of tape as the preferred form of tape media used for data storage. Examples of popular data storage tape cartridges are 3M's DC600, IBM's 3480 and DEC's TK/50.
In many data processing environments, it is useful to have on-line access to a selection of tape cartridges. One way to accomplish this is to utilize a magazine that holds a stack of tape cartridges. The magazine can be incremented either up or down so that a tape cartridge loader can access the selected tape cartridge and load it into an associated tape drive. See for example, U.S. Pat. No. 5,045,958 granted Sep. 3, 1991 to Leonard, et al. and assigned to Storage Technology Corporation. While this approach is serviceable, the number of tape cartridges that can be held in the magazine is limited. A much more expansive library of tape cartridges can be stored in a linear arrangement in racks or in carrousels. See for example, U.S. Pat. No. 5,065,265 granted Nov. 12, 1991 to Michel A. Pierrat.
Heretofore mass storage systems for magnetic tape cartridges have required custom cabinets. They have not been flexible in terms of capacity and they have been relatively expensive. Furthermore, they have not easily permitted a user to grow its library of tape cartridges.